The Chinese military recently published a notice inviting researchers to devise a weapon that sounds like a sort of electromagnetic rail gun—which uses magnetism instead of gunpowder to fire shells—that several nations are developing. But actually deploying railguns has been hampered by the size of the weapon and especially the vast amount of electrical energy needed to propel a shell to speeds of greater than Mach 7. For example, despite years of research and vast sums of money, the U.S. Navy appears less than optimistic about fitting railguns on its warships.

But Chinese scientists believe that magnetized plasma artillery will be so light and energy-efficient that it can be mounted on tanks.

Military vehicles carrying Chinese-made drones march past the Tiananmen Rostrum during the military parade to commemorate the 70th anniversary of the victory in the Chinese People's War of Resistance Against Japanese Aggression in Beijing, China, 3 September 2015 (Imaginechina via AP Images)

For years, drone warfare has been an essentially American pursuit. The new age of armed robots has been symbolized by Predators and Reapers spewing Hellfire missiles.

But guess who's the biggest exporter of combat drones? China.

"In 2014–18 China became the largest exporter in the niche market of unmanned combat aerial vehicles (UCAVs), with states in the Middle East among the main recipients," according to the Stockholm International Peace Research Institute, which compiles estimates of global military strength and arms spending.